基频谐振
振动系统的最低谐振。该谐振不一定是主谐振。对于超声叠堆，该谐振通常是弯曲谐振。
该术语也常用于指某一特定模态 —— 例如轴向模态的基频谐振、弯曲模态的基频谐振、径向模态的基频谐振等。见 Kinsler，第 46、53 - 54 页
Fundamental resonance
The lowest resonance of a vibrating system. This resonance is not necessarily the primary resonance. For an ultrasonic stack, this resonance is most often a flexural resonance.
This term is often applied to a particular mode -- e.g., the fundamental resonance of the axial mode, the fundamental resonance of the flexural mode, the fundamental resonance of the radial mode, etc. See Kinsler, pp. 46, 53 - 54